1. Field of the Invention
The present invention relates to a barrier device and a stereoscopic image display device using the barrier device. More particularly, the present invention relates to an active barrier capable of varying display patterns and a stereoscopic image display device using the active barrier.
2. Description of the Related Art
In general, people perceive a stereoscopic effect physiologically and experientially. In three-dimensional image display technology, a stereoscopic effect of an object is produced by using binocular parallax, which is a primary factor in recognizing a stereoscopic effect at a short distance. Stereoscopic images are viewed by a stereoscopic method that involves wearing of spectacles or by an autostereoscopic method that does not involve wearing of spectacles.
The stereoscopic method is classified into an anaglyph method that involves wearing of spectacles having blue and red lenses on respective sides, a polarization method that involves wearing of polarizing spectacles having different polarization directions, and a time-division method that involves wearing of spectacles including an electronic shutter synchronized with intervals by which a frame is repeated time-divisionally. As such, each stereoscopic method requires the inconvenience of wearing the spectacles, and causes difficulty of viewing objects other than the stereoscopic image. Accordingly, the autostereoscopic method that does not involve wearing of spectacles has been actively developed.
Typical autostereoscopic methods include a lenticular method in which a lenticular lens plate having an array of vertically arranged cylindrical lenses is formed in front of an image panel, and a parallax barrier method that separates left-eye and right-eye images using a barrier to obtain a stereoscopic effect.
In general, a barrier having alternately arranged opaque regions and transparent regions is placed in front of an image panel. The image panel includes right-eye pixels viewed by the right eye and left-eye pixels viewed by the left eye.
When an observer sees an image displayed on the image panel through the transparent regions of the barrier, different areas of the displayed image are respectively viewed by the right and left eyes even though they may be viewed through the same transparent region. That is, the stereoscopic effect is produced since the right and left eyes of the observer respectively view different images displayed on pixels neighboring each other through the same transparent regions.
Such a barrier is a two-view parallax barrier having the same width of the opaque and transparent regions, which has a problem in that a horizontal resolution is about a half of a vertical resolution. Recently, display devices capable of rotating its screen between a vertically long portrait screen mode and a horizontally long landscape screen mode have been developed. Specifically, the landscape screen mode is typically used for playing games, watching TV or motion pictures, and using the screen to see wide pictures captured by a built-in digital camera. However, the barrier is manufactured to be suitable for only one of the portrait and landscape modes. Therefore, the stereoscopic images are not available on a screen of the landscape mode when a barrier for the portrait mode is combined with the display device.
A conventional barrier method for displaying a 4-view parallax stereoscopic image is disclosed in U.S. Pat. No. 5,949,390.
In U.S. Pat. No. 5,949,390, respective right-eye images corresponding to each view are displayed on four cells (or pixels) arranged in sequence on a display panel, and a four-view image is viewed by the right eye through a corresponding transparent region. In a like manner, respective left-eye images corresponding to each view are displayed on four cells (or pixels) arranged in sequence on the display panel, and another four-view image is viewed by the left eye through a corresponding transparent region.
In the conventional barrier method described above, the barrier has wider opaque regions than the transparent regions, in order to express a stereoscopic image in a multi-view scheme having a greater number of views than the two-view scheme.
For those reasons, it has been difficult to popularize the stereoscopic image display device. Accordingly, it is highly desirable to develop a barrier that is adaptive to display 3D images in various schemes.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.